As one of the processes for manufacturing a semiconductor device, there may be a process of forming a thin film on a substrate in a process chamber, which is heated to a film forming temperature, by supplying a precursor gas or a reaction gas from a nozzle, which is heated to the film forming temperature, to the substrate. During this film forming process, deposits such as a thin film are adhered to the interior of the process chamber. Therefore, a cleaning process of removing the deposits adhered to the interior of the process chamber may be performed by supplying a cleaning gas into the process chamber after the film forming process.
During the above-mentioned film forming process, the deposits are adhered to the interior of the nozzle heated to the film forming temperature as well as the interior of the process chamber. However, in some cases, even the above-mentioned cleaning process may not remove the deposits from the interior of the nozzle.